Hbo Clinical Application

According to Zamboni6 HBO should be applied on compromised transferred tissues, if appropriate criteria exist such as: definition of problem, documentation of flap perfusion, suitable pre -HBO surgical procedures (if required) and minimal timing of HBO initiation.

The responsible plastic surgeon should define the underlying problem, providing the hyperbaric physician with the relevant information about the compromised tissue.

HBO treatments are performed at a pressure of 2.0 to 2.4 ata, in periods of 90 min. every 12 hrs for 2-3 days and then, as soon clinical stabilization occurs, once per day to a total of 20-30 treatments.

In case of total venous or arterial occlusion, specifically in free tissue transfer, treatments are given any 8 hrs for 24 hrs and then any 12 hrs for 48hrs followed by once daily.

Although clinical judgment is the most objective criterion for prediction of tissue survival outcome, Wattel et al.119 proposed transcutaneous oxygen measurement (TcPO2) in hyperbaric conditions to evaluate oxygen availability and therefore healing probability. Authors compared transferred tissue measurements under three successive conditions, first breathing normal air, then breathing pure oxygen by facial mask in normobaric and finally in hyperbaric conditions (2.5 ata). Only the measurements in hyperbaric conditions showed a significant difference and these values were predictive to the response of HBO treatment. Furthermore they have found that the flap failed if TcPO2 was lower than 50 torrs in HBO conditions.

Alternatively, others6 have found microvascular perfusion monitoring through Laser Doppler being more predictive of outcome than TcPO2, since in case edema is present acquired values may not be accurate.

Continuous Laser Doppler measurement depicts the dynamic condition of skin blood flow and may be of predictive value, whereas a single even normal value is not an adequate index of flap perfusion.

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